Flat panel loudspeakers are well-known, and typically consist of a rigid panel of laminated plastics, card or wood with an acoustic transducer attached to one face of the panel. Typical transducers are moving coil electromagnetic devices or piezoelectric devices. On a smaller scale, it has been proposed to attach a transducer to a greetings card to permit the card to deliver an audible message, or music, in addition to the written or printed matter on the card. Devices of this type are disclosed in WO 97/09842, for example.
It has now been found that a flexible sheet material, such as may be used to a make a window blind or the like, may be caused to act as an effective sound radiator.